This invention relates generally to exercise equipment and particularly to an exercise device that not only simulates free weights, but surpasses free weights in providing non deleterious loads for exercising the various muscle groups. Physical fitness is a goal that is pursued by a large number of people who regularly perform some type of exercise, whether in a home environment or in a special exercise facility, such as a health club or fitness center. The exercise facility generally includes a variety of exercise machines and equipment, ranging from very simple to very elaborate. The stack weight type of exercise equipment is generally considered to be superior to devices that rely upon springs, rubber bands, or velocity loading to provide a load against which the muscles of the person doing the exercising must work. This is because spring loading mechanisms characteristically vary in force or load delivery and are not really comparable to the loads provided by a free weight workout. Velocity type devices are even worse since their load delivery is a function of speed of movement.
Health clubs and fitness centers generally employ elaborate stack weight exercise machines, which have stacks of weights that are lifted by one or more cables. The weights are usually captive, that is, confined to movement in a track or path. Such machines force the user to adapt to the machine since the lifting bar has a generally fixed position. The same holds true for the other user operated devices on the exercise machine. Consequently, the user often finds himself severely restricted in the range of movements of his muscles when using the lifting (or pull down) bar on such machines. These restrictions on muscle movement impose unnatural and potentially harmful stresses and strains on the joints, muscles and tendons of the user. Problems of the above type are compounded in exercise machines that are designed for home use. Further, in a home environment, the weight and bulk of free weights and stack weights, coupled with the inherent dangers associated therewith to person and property, strongly militate against their use. Consequently, most home exercise devices and equipment rely upon springs, heavy duty rubber bands and velocity loading devices for developing the necessary forces to enable the user to experience a beneficial workout.
Adjustments in the load force provided by the mechanisms are generally inconvenient to make and often there is very little accuracy in determining the load change associated with the adjustment. Yet this is not the major drawback of such machines. By far the biggest failing of home type exercise machines is the nonuniform loads exhibited by the machines (and imposed upon the muscles of the user) during the exercise stroke or cycle. The resistance loading of rubber bands or straps and springs is inherently nonlinear and increases with the degree of stretching experienced. Consequently, the load resistance is much higher at the fully stretched position than it is when the device is close to the relaxed position. Similarly, velocity type load devices offer very high resistance to rapid movements and practically no resistance to slow movements. This, incidentally, is also the problem with devices using friction and hydraulics, in which the resistance developed is a function of speed of movement or the amount of force applied.
While certain prior art devices superficially appear to operate in a manner similar to the present invention, they are, in fact, significantly different. The invention, as will be seen, employs an articulated triangular lever arm system having a spring means with a free length as one arm thereof, with adjustments in loading being made by adjusting the lengths of any combination of two arms of the articulated triangular lever arm system.
A prior art published patent application to Horng EP 0135346 includes a damper (a hydraulic cylinder) that provides resistance to movement. The damper is not a spring, has no free length and affords a resistance that is a function of the applied force. The device includes a variable orifice arrangement for the hydraulic cylinder for adjusting the resistance offered. The Sowell U.S. Pat. No. 4,880,227 similarly discloses a hydraulic cylinder (dashpot) as the load imparting device. While a triangular lever arm system is shown, the hydraulic cylinder has no free length and merely adjusts its static position as required by any change in the other arms of the system.
The above patents are representative of the state of the art. Neither simulates the free weight loading achieved by the present invention.
It is well known that to maximize muscle development and exercise, the load experienced by the muscle should, optimally, be constant. Measured against this criterion of constant loading, even free weights and professional stack weight lifting equipment fail and can be shown to be quite erratic in muscle loading. This is due to the large inertia of the weights. The results of bench pressing with free weights, for example, clearly shows that the loading varies from practically zero at the top of the stroke to a severe overload at the bottom of the stroke due to the inertia of the weights. Large variations in loading not only result in a much lower average workout for the muscles, but can be very injurious to the muscle structure.
The exercise device of the present invention solves the problems inherent in all such devices. Further, the inventive system surpasses the exercise effect of free weights while avoiding the inconvenience and danger of free weights. Also, with the invention, the user is not confined to movements imposed by conventional exercise machines even though it includes an attached lifting bar. This is due to a novel coupling arrangement that permits universal movement of the lifting bar with respect to the lifting mechanism and a provision for rotation of the bar around its axis. The exercise device of the invention also enables a simple conversion from lifting exercises to pull down exercises without requiring the disassembling of any components of the machine. The inventive device is used with a novel aesthetically pleasing tubular frame for strength and simplicity. A pivotable bench is also included for conveniently converting from bench to non bench type exercises.